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  <title>正切</title>

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</div><hr /><div id="function.tan" class="refentry">
   <div class="refnamediv">
    <h1 class="refname">tan</h1>
    <p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">tan</span> &mdash; <span class="dc-title">正切</span></p>

   </div>
 <div class="refsect1 description" id="refsect1-function.tan-description">
  <h3 class="title">说明</h3>
   <div class="methodsynopsis dc-description">
    <span class="type">float</span> <span class="methodname"><strong>tan</strong></span>
     ( <span class="methodparam"><span class="type">float</span> <code class="parameter">$arg</code></span>
    )</div>

    <p class="para rdfs-comment">
     <span class="function"><strong>tan()</strong></span> 返回参数 <em><code class="parameter">arg</code></em> 的正切值。参数
     <em><code class="parameter">arg</code></em> 的单位为弧度。
    </p>
   </div>

   <div class="refsect1 parameters" id="refsect1-function.tan-parameters">
  <h3 class="title">参数</h3>
  <p class="para">
   <dl>

    
     <dt>
<em><code class="parameter">arg</code></em></dt>

     <dd>

      <p class="para">
       要处理的以弧度为单位的参数
      </p>
     </dd>

    
   </dl>

  </p>
 </div>

 <div class="refsect1 returnvalues" id="refsect1-function.tan-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   <em><code class="parameter">arg</code></em> 的正切值
  </p>
 </div>

 <div class="refsect1 examples" id="refsect1-function.tan-examples">
  <h3 class="title">范例</h3>
  <p class="para">
   <div class="example" id="example-3387">
    <p><strong>Example #1 <span class="function"><strong>tan()</strong></span> 例子</strong></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /><br /></span><span style="color: #007700">echo&nbsp;</span><span style="color: #0000BB">tan</span><span style="color: #007700">(</span><span style="color: #0000BB">M_PI_4</span><span style="color: #007700">);&nbsp;</span><span style="color: #FF8000">//&nbsp;1<br /><br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

   </div>
  </p>
 </div>

 <div class="refsect1 seealso" id="refsect1-function.tan-seealso">
  <h3 class="title">参见</h3>
  <p class="para">
   <ul class="simplelist">
    <li class="member"><span class="function"><a href="function.atan.html" class="function" rel="rdfs-seeAlso">atan()</a> - 反正切</span></li>
    <li class="member"><span class="function"><a href="function.atan2.html" class="function" rel="rdfs-seeAlso">atan2()</a> - 两个参数的反正切</span></li>
    <li class="member"><span class="function"><a href="function.sin.html" class="function" rel="rdfs-seeAlso">sin()</a> - 正弦</span></li>
    <li class="member"><span class="function"><a href="function.cos.html" class="function" rel="rdfs-seeAlso">cos()</a> - 余弦</span></li>
    <li class="member"><span class="function"><a href="function.tanh.html" class="function" rel="rdfs-seeAlso">tanh()</a> - 双曲正切</span></li>
    <li class="member"><span class="function"><a href="function.deg2rad.html" class="function" rel="rdfs-seeAlso">deg2rad()</a> - 将角度转换为弧度</span></li>
   </ul>
  </p>
 </div>

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